Just another Nat P

[pereze]

Well, I ordered most of the parts in December of 2007....how sad is that? I built a pair of Dayton III's and was very impressed, especially given my complete noobness. I am finally going to get started soon (maybe even tonight). Even with all the builds and information, I still have some questions.

My plan is to build the tower version. I would love to try a curved cabinet, but I am afraid the work involved will impede my progress and cause the project to take MUCH longer than needed. I have seen the drawings for the ~50L version with the down firing port and am leaning toward that. I have read about the Precision Port but there seems to be conflicting information on the port length compared to using PVC. (note: I only have Macs at home so I have not found a box software that would let me model this myself which is why I am asking). What length port given about 50L? I am not sure if I should just use PVC or get the Precision Port? Thoughts?

I will be using MDF for construction. I was planning on using 2 .5in pieces to make a 1in thick front baffle with .75in sides. I have read that some use 2 .75in pieces to make a 1.5in front baffle. Is that needed?

As far as the crossover, I have bought some of the parts already. I need to purchase the inductors and a few more caps. I was planning on ordering everything from Parts Express. I am using the Dayton Caps and Dayton resistors. I am planning on getting the Jantzen 15awg air core inductors. I could save a lot of money by getting the 18 or 20awg but wasn't sure what I am giving up. Is there a big difference? Ok, that may not be fair, but would the average Joe notice the difference?

I plan on lining the cabinet with foam. Again, I have read different reviews of different fabrics and foams. What would you recommend for the Foam?

Here's to hoping this doesn't take me a year to accomplish! :T

Thanks in Advance,
Eric

[wkhanna]

This may help.

https://www.htguide.com/forum/showthread.php?t=22639&highlight=nat+journey

[pereze]

Thanks for the link Bill. I remember reading this way back in the day. HA!
I specifically remember the "feet" iterations.

The only problem is now you have given me a different design to consider. i really like the angular look. DOH!

And not sure if you still have the Bt3100 but I wish I still had mine. It was a great little saw. I have a bigger saw so I can't complain, but I really think that saw did everything I really needed and took up WAY less room.

I assume you are still enjoying your Nat P's?

Thanks,
Eric

[jmik26]

I just got done building the Nat P's. After sorting out some user errors I am enjoying them. Here is the thread https://www.htguide.com/forum/showthread.php?t=38382

I started off the same way, wanting a curved cabinet. I went ahead and routed all the templates and bracing with great success but miserable failed at the attaching sides part with kerfed MDF. Eventually I scrapped the idea for now, it took to long to calculate, plain, clamp, etc... Went and picked up a new sheet of wood and spanked out the square cabinets in a day compared to weeks planning, autocad layout, and fine tuning with curved. Anyhow, I will give it another shot in the future but will go with thin sheets of plywood instead. Here is the start of the curved journey for me, good info on some links and suggestions. https://www.htguide.com/forum/showthread.php?t=38276

I built my square Nat P's roughly 48 liters or 1.69 ft^3. Everything is .75" MDF and have not had any problems yet. For my ports I have used 3" PVC with elbow 11" long as the original thread from evil twins suggests for maximum low end. I didn't use any fancy flares, just straight PVC and I have no port noise. I have spent the last week messing with port length and found out that I like the port 11" and the speakers are sufficient enough with bass that I don't want a sub for right now. I have audition them for two different people and both swear the sub was on . In my build thread you can see the BOM from Parts Express and awg's of coils. Not sure if it was necessarily to get the better coils but I spent the few extra dollars to be safe since there are only a couple. Lastly the foam, I ended up ripping all the foam off the side walls to get my Nat P's sounding the way I liked them but I think thats personal preference. I only attached with staples so it was a easy fix.

I'm no expert but I will help in anyway I can, keep us posted!

[wkhanna]

Hi Eric!

Yup, still have the bt3100. No regrets there.

& still enjoying the 'Twins', too!

One thing I have learned over the time I’ve been listening to them is the effect that having the angled baffle made. As my source & power components have been upgraded over time, I discovered that the 15º slope on baffle will degrade the performance. I believe it effected the time coherence as sound waves from the top & bottom woofers were arriving at the listening point at different times. This caused a ‘smearing’ of the sound. I have since adjusted the feet such that the baffle is now perpendicular to floor.

The change in the sound was V significant. The LF & mid bass tightened up & has a clear, clean & sharp leading edge. Mids now are crystal clear and seem more balanced relative to the HF. But most dramatic is the transformation of the Pace, rhythm & timing. Your toe begins to tap immediately. Before, it seemed like each instrument was following its own conductor, now, instruments and vocals all work together. Regardless of the genre, all music sounds more ‘live’ & alive.

Again, this all became more evident as the quality of the source & power devices improved. The bottom line is that a properly executed build of the Nat P will deliver a speaker with the quality and ability to resolve and deliver with great accuracy exactly what is on the source material.

[fbov]

Tilting the baffle of an MTM, or any other driver array, away from the design axis is a bad idea. It just points the on-axis sound lobe at the ceiling, and one of the midrange nodes at the listener. Glad to hear you found the right solution...

Have fun,
Frank

[pereze]

OK, so definitely no angles. I picked up some 1/4 in MDF to play with the curved side idea. I think it will take the bend fairly well, but what do I know.

Thanks,
Eric

[Johnnz]

Hi Eric,
How is progress? Got a design nailed down yet? I too have had intentions to build the Nat P for over a year - sheesh - make that nearly three years! Just noticed I printed off the the orignial build thread in August '08!

Anyway, I have ordered all drivers and XO parts last week so will be on my way soon.
For a long while I wanted to make a curved front and rear tower design, and I had nutted out a method I could confidently construct the cabinets in MDF (using CNC router and sandwiching "S" shaped curved pieces together for front and rear panels) but as I want to have a real wood veneered finish I figure it would be wiser to tackle a flat surfaced project for my first veneering venture, which won't require a vacuum press.

Will try to make a build thread in here once I am started. Hope things are going to plan with your build.